JP4284996B2 - Cam follower and method of manufacturing the roller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cam follower and a method for manufacturing the roller .
[0002]
[Prior art]
In the conventional cam follower, a support shaft is spanned on a bifurcated side wall for holding a roller formed on a body, and the roller is rotatably supported on the outer periphery of the support shaft via a plurality of needle rollers. (For example, refer to Patent Document 1). A cam is in contact with the outer diameter surface of the roller.
[0003]
Both end surfaces of the roller are flat surfaces along the radial direction, and are opposed in parallel to the inner surfaces of both side walls. However, a round chamfer is given to the corner portion of the outer diameter surface of the roller mainly to remove the edge. This chamfering is generally called R chamfering, and the axial length and the radial length have a 1: 1 relationship. In some cases, the chamfer may be an inclined surface, but in this case, the axial length and the radial length are in a 1: 1 relationship.
[0004]
[Patent Document 1]
Registered Utility Model No. 2745844 (Fig. 1)
[0005]
[Problems to be solved by the invention]
In the above conventional example, during the rotation of the roller, for example, when the roller moves in the axial direction and the flat portion on one end side of the roller is pressed against the inner surface of one side wall, the roller comes into sliding contact. In this sliding contact portion, since the flat portion of the one end surface of the roller is in contact with the surface, there is a concern that the frictional resistance becomes large, the torque is increased, and heat is easily generated. Further, when the roller is inclined with respect to the shaft center, the R chamfered portion is pressed against the inner surface of one side wall, and there is a concern about local wear due to stress concentration.
[0006]
[Means for Solving the Problems]
The cam follower of the present invention includes a metal body having a pair of opposing side walls, a support shaft attached in a state of being spanned between the pair of side walls of the body, and a region between the pair of side walls on the support shaft. An inner diameter side that is rotatably mounted through a plurality of needle rollers and is in rolling contact with the needle rollers on the inner peripheral surface, and is in rolling contact with a cam having a contact surface wider in the axial direction than the outer peripheral surface on the outer peripheral surface. A cylindrical roller having the same axial length on the outer diameter side and the axial length on the outer diameter side, and chamfered on each of the corners on the outer diameter side and the inner diameter side on both end faces of the roller, The relationship between the axial length dimension A1 of the chamfer on the side and the axial length dimension A2 of the chamfer on the inner diameter side is set to A1 <A2.
[0007]
In this case, chamfering is performed on both the outer diameter side and the inner diameter side on both end faces of the roller. Therefore, since the planar area of both end faces of the roller is reduced, even if one end face of the roller is pressed against the inner surface of one side wall and makes sliding contact with the inner side surface of the side wall, the sliding contact The frictional resistance due to can be reduced. Further, in the sliding contact state, a gap formed between the one end surface of the roller and one side wall is increased, so that the lubricant present around the roller is easily introduced into the sliding contact portion.
Further, the lubricant is easily introduced to the inner diameter side of the roller while sufficiently securing the axial width of the contact surface with the cam on the outer peripheral surface of the roller.
[0012]
The method for manufacturing a cam follower roller according to the present invention includes a metal body having a pair of opposing side walls, a support shaft attached in a state of being spanned between the pair of side walls of the body, and the pair of shafts on the support shaft. A roller that is rotatably mounted in a region between the side walls and is in contact with a cam, and the axial length dimension is A1 and the radial length dimension at the outer diameter side corners on both end faces of the roller. B1 is a method of manufacturing the roller of the cam follower that has been chamfered, wherein at least an outer diameter surface of the roller is prepared, the roller is fitted into a cylindrical receiving mold, By pressing both ends in the axial direction of the roller, the outer diameter of which is constrained by the receiving die, with a pressing die, the roller is compressed by a predetermined amount in the axial direction, the outer diameter surface and the end surface of the roller are forged, and the outer surface of the roller is in diameter, A1 < It is intended to obtain a first chamfer.
According to another method of manufacturing a cam follower roller of the present invention, a metal body having a pair of opposing side walls, a support shaft attached in a state of being spanned between the pair of side walls of the body, A roller that is rotatably mounted in a region between a pair of side walls and that is in contact with a cam. An axial length dimension is A2 at a corner on the inner diameter side at both end faces of the roller , and a radial length dimension. B2 is a method of manufacturing the roller of a cam follower with chamfering, wherein at least an inner diameter surface of the roller is unprocessed on the outer periphery of a cylindrical mold from one side in the axial direction. By relatively pushing in so as to be fitted, the inner diameter side region on the end surface on one side in the axial direction of the roller is caused to form a chamfer on the inner diameter side on one side in the axial direction, and on one side in the axial direction. the chamfer on the inner diameter side a of <The chamfer dimension of B2, for also the other axial side of the roller, by pressing the roller against the mold cylindrical, that the inner diameter side of the other axial side get chamfer chamfer dimension of A2 <B2 It is.
[0020]
The chamfered bus bar shape may be a curve or a straight line.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
1 to 7 show an embodiment of the present invention. In the figure, 1 is a cam and 2 is a cam follower.
[0022]
The cam follower 2 includes a body 3 having a pair of opposite side walls 3a and 3b, a support shaft 4 attached in a state of being spanned between the pair of side walls 3a and 3b, and a pair of side walls 3a and 3b in the support shaft 4. And a roller 5 that is rotatably mounted in the region. In operation, the rotating cam 1 is brought into contact with the outer peripheral surface of the roller 5 so that the body 3 is reciprocated in a predetermined direction. In FIG. 1, a plurality of needle rollers 6 are interposed between the support shaft 4 and the roller 5. However, the needle rollers 6 are eliminated and the roller 5 is brought into sliding contact with the support shaft 4. May be.
[0023]
In this embodiment, while the rotation operation of the roller 5 is made smooth, it is devised to improve the seizure resistance and the wear resistance between the roller 5 and the side walls 3a and 3b. .
[0024]
As shown in FIG. 2, both end surfaces of the roller 5 are chamfered 5b and 5c having the following characteristics at the outer and inner corners of the both end surfaces 5a and 5a of the roller 5, respectively. Yes.
[0025]
Specifically, in the chamfer 5b on the outer diameter side, the relationship between the axial length dimension A1 and the radial length dimension B1 is set to A1 <B1. In the chamfer 5c on the inner diameter side, the relationship between the axial length dimension A2 and the radial length dimension B2 is set to A2 <B2. Furthermore, the relationship between the axial length dimension A1 of the outer diameter side chamfer 5b and the axial length dimension A2 of the inner diameter side chamfer 5c is set to A1 <A2. The sum of the radial length B1 of the outer diameter side chamfer 5b and the radial length B2 of the inner diameter side chamfer 5c is set so as not to exceed the wall thickness of the roller 5.
[0026]
Such a roller 5 is manufactured by a forging process, and the chamfer 5b on the outer diameter side and the chamfer 5c on the inner diameter side are simultaneously formed in the forging process. That is, the roller 5 is manufactured by forging the outer diameter surface, the inner diameter surface, and the end surface using a steel pipe, for example, by dividing it into a plurality of times, and finally performing a polishing process as necessary. The chamfers 5b and 5c of the roller 5 are formed in the forging process. This forging process will be described in detail.
[0027]
First, the outer diameter side chamfer 5b is formed at the same time when the outer diameter surface of the roller 5 is forged. That is, as shown in FIG. 3, a steel pipe is cut to a predetermined length to prepare a roller 5 whose both ends in the axial direction on the outer diameter side are inclined, and this roller 5 is fitted into a cylindrical receiving die P1. Put in. Then, as shown in FIG. 4, both end surfaces in the axial direction of the roller 5 whose outer diameter is constrained by the receiving die P1 are pressed by the pressing dies P2 and P2, thereby compressing the roller 5 in the axial direction by a predetermined amount. Thereby, the outer diameter surface and end surface of the roller 5 are forged. By repeating such a process several times, the slack at both axial ends on the outer diameter side of the roller 5 is reduced, and the chamfer 5b having the above-described characteristics is obtained on the outer diameter side of the roller 5.
[0028]
Next, the chamfer 5c on the inner diameter side is formed at the same time when the inner diameter surface of the roller 5 is forged. That is, as shown in FIG. 5, the roller 5 having the chamfer 5 b as described above is pushed in from the one side in the axial direction in a form that is externally fitted to the cylindrical mold Q. Thereby, the inner peripheral surface of the roller 5 is dragged to the other side in the axial direction by friction with the mold Q, and the inner diameter side region of the end surface 5a on one side of the roller 5 is inclined to the other side in the axial direction. The inner diameter side chamfer 5c is formed by utilizing this sagging, and the above-described steps are repeated several times to obtain the desired chamfer dimension as described above in the chamfer 5c. By performing the same process on the other side of the roller 5, a chamfer 5 c similar to the one side is formed on the other end surface of the roller 5. The mold Q may be pushed into the inner diameter of the roller 5.
[0029]
The formation of the chamfers 5b and 5c on the outer diameter side and the inner diameter side is not limited to the above-described process. For example, a chamfered pressing die is directly pressed against the inner diameter side or the outer diameter side of the end surface of the roller 5. It may be formed. Moreover, you may perform a hardening process separately with respect to the internal diameter surface and outer diameter surface of the roller 5. FIG. Further, the generatrix shape of the chamfers 4b and 4c may be a straight line or a curved line.
[0030]
In the embodiment described above, chamfers 5b and 5c are provided on the outer diameter side and the inner diameter side of both end faces 5a of the roller 5, and the chamfer dimensions of these chamfers 5b and 5c are devised. Thereby, in the chamfering on the outer diameter side, there are the following operations and effects compared to the conventional example in which the chamfering dimension in the axial direction and the chamfering dimension in the radial direction are in a 1: 1 relationship.
[0031]
That is, since the planar area of the both end surfaces 5a and 5a of the roller 5 is smaller than that of the conventional example, during the rotation of the roller 5, for example, the roller 5 slides in the axial direction and the one end surface 5a of the roller 5 becomes one side wall 3a. (Or 3b) When pressed against the inner surface of the roller 5, the planar area of the one end surface 5a of the roller 5 is in sliding contact with the inner surface of one of the side walls 3a (or 3b). The frictional resistance due to sliding contact can be reduced.
[0032]
Further, since the radial lengths of the chamfers 5b, 5b on the outer diameter side of the both end faces 5a, 5a of the roller 5 are set larger than in the conventional example, for example, the axis of the roller 5 is rotated during the rotation of the roller 5. Is inclined and the chamfer 5b on the outer diameter side of the one end surface 5a of the roller 5 is pressed against the inner surface of the one side wall 3a (or 3b), the chamfer 5b on the outer diameter side becomes the one side wall 3a ( Alternatively, the surface comes into sliding contact with the inner surface of 3b), and the concentration of contact stress can be suppressed.
[0033]
Further, in the sliding contact state, a gap formed between the one end surface 5a of the roller 5 and one side wall 3a (or 3b) is larger than that in the conventional example, and the lubricant present around the roller 5 is in contact with the sliding contact. Easy to be introduced into the part.
[0034]
As a result of these synergies, the frictional resistance of the sliding contact portion can be moderately reduced, contributing to the torque reduction of the roller 5, and the inner surface of the one end surface 5a of the roller 5 and one side wall 3a (or 3b). And the local wear of the side wall 3a (or 3b) can be suppressed. As a result, the smooth rotation of the roller 5 and the seizure resistance and wear resistance between the roller 5 and the inner surfaces of the side walls 3a and 3b can be improved.
[0035]
Further, the cam 1 on the outer peripheral surface of the roller 5 is set by setting the relationship between the axial length dimension A1 of the chamfer 5b on the outer diameter side and the axial length dimension A2 of the chamfer 5c on the inner diameter side to A1 <A2. While sufficiently securing the axial width of the abutting surface, the above-described operations and effects are remarkably exhibited such that the lubricant is easily introduced into the inner diameter side of the roller 5.
[0036]
Further, since the chamfers 5b and 5c are formed by forging, a post-process such as cutting is not required, which can contribute to a reduction in manufacturing cost.
[0037]
In addition, this invention is not limited only to embodiment mentioned above, Various application and deformation | transformation can be considered. For example, in the roller 5, only one of the chamfer 5b on the outer diameter side or the chamfer 5c on the inner diameter side can be applied.
[0038]
By the way, the cam follower 2 described above can be used for rocker arms 10 and 20 of an engine valve mechanism such as an automobile as shown in FIGS. Of course, the cam follower 2 can be used for rocker arms other than these rocker arms 10 and 20 and various other cam mechanisms.
[0039]
The rocker arm 10 shown in FIG. 6 is called a center pivot type. The cam follower 2 is provided at one end in the longitudinal direction of the body 3, the rocker shaft 30 is penetrated in the middle in the longitudinal direction, and the adjustment is performed at the other end in the longitudinal direction. The screw 11 is screwed. A stem end of a valve 31 of a valve mechanism installed in the cylinder head is brought into contact with the adjustment screw 11. As the cam 1 rotates, the body 3 is tilted with the rocker shaft 30 as a fulcrum, and the adjusting screw 11 is repeatedly displaced in the vertical direction, thereby opening and closing the valve 31.
[0040]
A rocker arm 20 shown in FIG. 7 is called an end pivot type. The cam follower 2 is provided in the middle of the body 3 in the longitudinal direction, a valve insertion portion 12 is provided at one end in the longitudinal direction, and an upward hemisphere is provided at the other end in the longitudinal direction. Each of the shaped pivot portions 13 is provided. The pivot portion 13 is engaged with the upper end of a lash adjuster 32 installed on a cylinder head (not shown). As the cam 1 rotates, the body 3 is tilted with the pivot portion 13 as a fulcrum, and the valve insertion portion 12 is repeatedly displaced in the vertical direction to open and close the valve 31.
[0041]
【The invention's effect】
In the present invention, for example, when the roller slides in the axial direction and the one end surface of the roller is pressed against the inner surface of one of the side walls to be in sliding contact, the sliding contact portion The frictional resistance of the roller can be reduced, contributing to the reduction in the torque of the roller, and when the axis of the roller is tilted, heat is generated between one end surface of the roller and the inner surface of one of the side walls, or local portions of the side walls. Wear can be suppressed. Therefore, according to the present invention, it is possible to provide a highly reliable cam follower, such as the smooth rotation of the roller, the seizure resistance between the roller and the side wall, and the wear resistance.
[Brief description of the drawings]
1 is a cross-sectional view showing a cam follower according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the upper half of the roller of FIG. 1. FIG. 3 is a cross-sectional view showing a process of forming a chamfer on the outer diameter side of the roller. 4 is a cross-sectional view showing a process following FIG. 3. FIG. 5 is a cross-sectional view showing a process of forming a chamfer on the inner diameter side of the roller. FIG. 6 is a side view showing an example of usage of the cam follower according to the present invention. FIG. 7 is a side view showing an example of usage of the cam follower according to the present invention.
DESCRIPTION OF SYMBOLS 1 Cam 2 Cam follower 3 Body 3a, 3b Body side wall 4 Support shaft 5 Roller 5a End face 5b of roller Chamfer 5a on the outer diameter side of roller Chamfer 6 on the inner diameter side of roller 6 Needle roller

Claims (3)

A metal body having a pair of opposing side walls, a support shaft attached in a state of being spanned between the pair of side walls of the body, and a plurality of needle rollers in a region between the pair of side walls on the support shaft The outer circumferential surface is in rolling contact with the needle roller, and the outer peripheral surface is in rolling contact with a cam having a contact surface that is wider in the axial direction than the outer peripheral surface. A cylindrical roller having an equal axial length on the radial side,
On both end faces of the roller, chamfering is applied to each corner on the outer diameter side and inner diameter side,
A cam follower in which a relationship between an axial length dimension A1 of the chamfer on the outer diameter side and an axial length dimension A2 of the chamfer on the inner diameter side is set to A1 <A2. A metal body having a pair of opposing side walls, a support shaft attached in a state of being spanned between the pair of side walls of the body, and being rotatably mounted in a region between the pair of side walls on the support shaft; A cam follower in which a cam is abutted, and chamfering is performed on both end faces of the roller with a chamfer having an axial length dimension A1 and a radial length dimension B1 at corners on the outer diameter side. A method of manufacturing the roller,
Prepare a roller with at least an outer diameter surface unprocessed, insert this roller into a cylindrical receiving mold, and add both end surfaces in the axial direction of the roller with the outer diameter restricted by the receiving mold with a pressing mold. The roller of the cam follower is characterized in that the roller is compressed by a predetermined amount in the axial direction, the outer diameter surface and the end surface of the roller are forged, and a chamfer of A1 <B1 is obtained on the outer diameter side of the roller. Production method. A metal body having a pair of opposing side walls, a support shaft attached in a state of being spanned between the pair of side walls of the body, and being rotatably mounted in a region between the pair of side walls on the support shaft; The cam follower includes a roller with which a cam is abutted, and chamfered with an axial length dimension of A2 and a radial length dimension of B2 at corners on the inner diameter side at both end faces of the roller. A method of manufacturing a roller, comprising:
At least the roller whose inner diameter surface is unprocessed is pushed into the outer periphery of the cylindrical mold from one side in the axial direction so as to be fitted on the outer periphery thereof, so that the end surface on the one side in the axial direction of the roller The inner diameter side region is chamfered by forming a chamfer on the inner diameter side on one side in the axial direction, and the chamfer dimension on the inner diameter side on one side in the axial direction is set to a chamfering dimension of A2 <B2. by pushing the roller against the mold a cylindrical, manufacturing method of a cam follower roller, characterized in that the inner diameter side of the other axial side get chamfer chamfer dimension of A2 <B2.

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